use ser::Error;
use serde::ser;
use std::str;

pub struct PartSerializer<S> {
    sink: S,
}

impl<S: Sink> PartSerializer<S> {
    pub fn new(sink: S) -> Self {
        PartSerializer { sink: sink }
    }
}

pub trait Sink: Sized {
    type Ok;

    fn serialize_bool(self, value: bool) -> Result<Self::Ok, Error>;

    fn serialize_static_str(self,
                            value: &'static str)
                            -> Result<Self::Ok, Error>;

    fn serialize_str(self, value: &str) -> Result<Self::Ok, Error>;
    fn serialize_string(self, value: String) -> Result<Self::Ok, Error>;
    fn serialize_none(self) -> Result<Self::Ok, Error>;

    fn serialize_some<T: ?Sized + ser::Serialize>
        (self,
         value: &T)
         -> Result<Self::Ok, Error>;

    fn unsupported(self) -> Error;
}

impl<S: Sink> ser::Serializer for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;
    type SerializeSeq = Self;
    type SerializeTuple = Self;
    type SerializeTupleStruct = Self;
    type SerializeTupleVariant = Self;
    type SerializeMap = Self;
    type SerializeStruct = Self;
    type SerializeStructVariant = Self;

    fn serialize_bool(self, v: bool) -> Result<S::Ok, Error> {
        self.sink.serialize_bool(v)
    }

    fn serialize_i8(self, v: i8) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_i16(self, v: i16) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_i32(self, v: i32) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_i64(self, v: i64) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_u8(self, v: u8) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_u16(self, v: u16) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_u32(self, v: u32) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_u64(self, v: u64) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_f32(self, v: f32) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_f64(self, v: f64) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_char(self, v: char) -> Result<S::Ok, Error> {
        self.sink.serialize_string(v.to_string())
    }

    fn serialize_str(self, value: &str) -> Result<S::Ok, Error> {
        self.sink.serialize_str(value)
    }

    fn serialize_bytes(self, value: &[u8]) -> Result<S::Ok, Error> {
        match str::from_utf8(value) {
            Ok(value) => self.sink.serialize_str(value),
            Err(err) => Err(Error::Utf8(err)),
        }
    }

    fn serialize_unit(self) -> Result<S::Ok, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_unit_struct(self, name: &'static str) -> Result<S::Ok, Error> {
        self.sink.serialize_static_str(name.into())
    }

    fn serialize_unit_variant(self,
                              _name: &'static str,
                              _variant_index: usize,
                              variant: &'static str)
                              -> Result<S::Ok, Error> {
        self.sink.serialize_static_str(variant.into())
    }

    fn serialize_newtype_struct<T: ?Sized + ser::Serialize>
        (self,
         _name: &'static str,
         value: &T)
         -> Result<S::Ok, Error> {
        value.serialize(self)
    }

    fn serialize_newtype_variant<T: ?Sized + ser::Serialize>
        (self,
         _name: &'static str,
         _variant_index: usize,
         _variant: &'static str,
         _value: &T)
         -> Result<S::Ok, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_none(self) -> Result<S::Ok, Error> {
        self.sink.serialize_none()
    }

    fn serialize_some<T: ?Sized + ser::Serialize>(self,
                                                  value: &T)
                                                  -> Result<S::Ok, Error> {
        self.sink.serialize_some(value)
    }

    fn serialize_seq(self, _len: Option<usize>) -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }


    fn serialize_seq_fixed_size(self, _len: usize) -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_tuple(self, _len: usize) -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_tuple_struct(self,
                              _name: &'static str,
                              _len: usize)
                              -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_tuple_variant(self,
                               _name: &'static str,
                               _variant_index: usize,
                               _variant: &'static str,
                               _len: usize)
                               -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_map(self, _len: Option<usize>) -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_struct(self,
                        _name: &'static str,
                        _len: usize)
                        -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }

    fn serialize_struct_variant(self,
                                _name: &'static str,
                                _variant_index: usize,
                                _variant: &'static str,
                                _len: usize)
                                -> Result<Self, Error> {
        Err(self.sink.unsupported())
    }
}

impl<S: Sink> ser::SerializeSeq for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_element<T: ?Sized + ser::Serialize>(&mut self,
                                                     _value: &T)
                                                     -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeTuple for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_element<T: ?Sized + ser::Serialize>(&mut self,
                                                     _value: &T)
                                                     -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeTupleStruct for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_field<T: ?Sized + ser::Serialize>(&mut self,
                                                   _value: &T)
                                                   -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeTupleVariant for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_field<T: ?Sized + ser::Serialize>(&mut self,
                                                   _value: &T)
                                                   -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeMap for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_key<T: ?Sized + ser::Serialize>(&mut self,
                                                 _key: &T)
                                                 -> Result<(), Error> {
        unreachable!()
    }

    fn serialize_value<T: ?Sized + ser::Serialize>(&mut self,
                                                   _value: &T)
                                                   -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeStruct for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_field<T: ?Sized + ser::Serialize>(&mut self,
                                                   _key: &'static str,
                                                   _value: &T)
                                                   -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}

impl<S: Sink> ser::SerializeStructVariant for PartSerializer<S> {
    type Ok = S::Ok;
    type Error = Error;

    fn serialize_field<T: ?Sized + ser::Serialize>(&mut self,
                                                   _key: &'static str,
                                                   _value: &T)
                                                   -> Result<(), Error> {
        unreachable!()
    }

    fn end(self) -> Result<S::Ok, Error> {
        unreachable!()
    }
}